This invention relates in general to wheel ends, and more particularly to a wheel end provided with a sensor and cable that together serve as a vent for a bearing in the wheel end.
More and more components of automotive vehicles are being furnished by outside suppliers as packaged assemblies. Typical are wheel ends used to couple the road wheels of the vehicles to suspension uprights that form part of the suspension systems for such vehicles. The typical wheel end has a housing that is bolted to a suspension upright, a hub provided with a spindle that projects into the housing, and an antifriction bearing located between the housing and spindle to enable the hub to rotate with respect to the housing. The road wheel is secured to a flange at the end of the spindle on the hub. The assembly procedure is such that upon completion the bearing has the correct setting—normally slight preload—and a measured quantity of grease for lubrication. A seal pressed into the outboard end of the housing and another seal or end cap pressed into the inboard end of the housing retains the lubricant in the bearing and excludes contaminants. Conditions may exist, such as a change in temperature or elevation, that cause the pressure within the bearing to increase. Indeed, if an end cap is pressed into the housing, it will function as a pump during assembly and increase the pressure within the bearing. Moreover, oils used in the manufacture of the bearing and in the assembly of the wheel end leach some of the oil out of the grease. The elevated pressure produced within the bearing may drive some of the free oil past the lips of the seals and out of the bearing.
Many wheel ends have speed sensors to monitor the angular velocity of their hubs. Active sensors are preferred. This type of sensor has a barrel that projects into the interior of the housing from a head, and both the head and barrel have electronic components embedded in them. The electronic components are totally isolated from contaminants, such as moisture, to which the wheel end may be subjected. As a consequence, the sensor has no through passage through which the interior of the bearing may be vented.